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authorTrond Myklebust <Trond.Myklebust@netapp.com>2006-06-09 09:40:27 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2006-06-09 09:40:27 -0400
commit28df955a2ad484d602314b30183ea8496a9aa34a (patch)
treec62632b2a0a49df114283f10764244c1b1b5f506 /fs/lockd/clntproc.c
parent5046791417dcac1ba126b77b8062af15a2f0b8e1 (diff)
downloadop-kernel-dev-28df955a2ad484d602314b30183ea8496a9aa34a.zip
op-kernel-dev-28df955a2ad484d602314b30183ea8496a9aa34a.tar.gz
NLM: Fix reclaim races
Currently it is possible for a task to remove its locks at the same time as the NLM recovery thread is trying to recover them. This quickly leads to an Oops. Protect the locks using an rw semaphore while they are being recovered. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/lockd/clntproc.c')
-rw-r--r--fs/lockd/clntproc.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index f96e381..4db6209 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -508,7 +508,10 @@ nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
}
block = nlmclnt_prepare_block(host, fl);
+again:
for(;;) {
+ /* Reboot protection */
+ fl->fl_u.nfs_fl.state = host->h_state;
status = nlmclnt_call(req, NLMPROC_LOCK);
if (status < 0)
goto out_unblock;
@@ -531,10 +534,16 @@ nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
}
if (resp->status == NLM_LCK_GRANTED) {
- fl->fl_u.nfs_fl.state = host->h_state;
+ down_read(&host->h_rwsem);
+ /* Check whether or not the server has rebooted */
+ if (fl->fl_u.nfs_fl.state != host->h_state) {
+ up_read(&host->h_rwsem);
+ goto again;
+ }
fl->fl_flags |= FL_SLEEP;
/* Ensure the resulting lock will get added to granted list */
do_vfs_lock(fl);
+ up_read(&host->h_rwsem);
}
status = nlm_stat_to_errno(resp->status);
out_unblock:
@@ -596,6 +605,7 @@ nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
static int
nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
{
+ struct nlm_host *host = req->a_host;
struct nlm_res *resp = &req->a_res;
int status;
@@ -604,7 +614,9 @@ nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
* request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
* case, we want to unlock.
*/
+ down_read(&host->h_rwsem);
do_vfs_lock(fl);
+ up_read(&host->h_rwsem);
if (req->a_flags & RPC_TASK_ASYNC)
return nlm_async_call(req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
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